Reenforced paper



Jan. 10, 1933. GIBBS 1,894,219

REENFORCED PAPER Filed April 5, 1931 ATTORNEY or reenforced waterproofpaper for the pur- Patented Jan. 10, 1933 UNITEDSTATES PATENT OFFICE-GEOBGE E. GIBBS, OF A'I'ILE'BOBD, HASSACEUSETTS, ASSIGNOB 1'0 AIEBIGANBEEN- FOMED PAPER GOMPANY, OF ATTLEBOBO, MASSACHUSETTS, A. CORPORATIONOF .IASSAGHUSETTS BEENFOBOED PAP EB Application filed April. 3, 1881.Serial No. 527,875.

This invention relates to reenforced sheet material and moreparticularly to a multiply reenforced sheet material havin means forfurther strengthening the multip y sheet material at spaced intervals.

It is found that by increasing the strength and durability of certainsheet materials they may be satisfactorily used in various fields as asubstitute for woven fabrics, and in many cases they are preferable towoven fabric due to the lower cost and the added protection afforded bythe property of the sheet material to exclude dirt and moisture.

For example strongly reenforeed paper is well adapted for use in theconstruction of sacks, bags and bale wrappers, and when employed forthese purposes gives better protection than burlap or other wovenfabrics due to the fact that the paper being devoid of'openings orinterstices will exclude dirt and moisture, particularly when the paperis waterproof.

Likewise strongly reenforced paper is well adapted for use as asubstitute for canvas in constructing tents, tarpaulins and the like,

,due to the fact that reenforced paper will exclude moisture better thanmost waterproof canvas, and is much cheaper than canvas.

The difiiculty in using reenforced paper,

poses above mentioned is due to the low strength of paper as comparedwith woven materials and to its tendency to tear or rupture understrain.

The present invention seeks to overcome this objectionable feature ofreenforced pa-' per and contemplates a multiply, reenforced, waterproofpaper that is provided with additional reenforcements at spacedpredetermined points, such as the portions of the reenforced paper whichare likely to be subpartly rolled bac The various features of theinvention will be further understood from the following descr ption whenread in connection with the drawing illustrating good practical formsthereof.

In the drawing Fig. 1 is a plan view of reenforced paper constructed inaccordance with the present invention, the upper sheet of paper beingproofing of the paper is readily accomplished,

by employing a waterproof adhesive to secure the sheets together. In theembodiments of the invention shown in Figs. 1 to 4 inclusive themultiply paper is formed of two sheets of paper 10 and 11, such askraft, or other tough, durable paper, and these two sheets of paper aresecured together preferably with g. waterproof adhesive, such as blackasphal- Since the strength of the multiply paper is an important featurethe sheets of paper 10 and 11 should be strongly reenforced byreenforcing material provided between the two sheets and secured theretoby the waterproofing adhesive, and while various forms of either wovenor unwoven materials may be employed to reenforce the sheets of paper,excellent results are secured through the employment of straightenedunspun fibers, such as sisal, as the reenforcing elements, and in theconstruction shown one layer of straight ened unspun fibers 12 issecured transversely between the two sheets of paper and a second layerof straightened unspun fibers 13 is secured longitudinally between thetwo sheets of paper. The advantage of using straight-' provided ened unfibers of relative long staple as the reen orcing elements resides inthe fact that these fibers will not elongate or stretch appreciablyunder tension and as a result when paper reenforced with these fibers 1splaced under tension the fibers will not stretch to subject the materialto a rupturingstrain but will resist the stretching force which wouldtear the paper if the fibers yield.

Each sheet of paper 10 and 11 preferably has a coating of waterproofadhesive applied to its inner face so that one layer of fibers will besecured to the sheet 10 by the adhesive upon its inner face and theother layer of fibers will be secured to the sheet 11 by the adhesiveapplied to the inner face of th1s sheet and the two sheets of paper willbe firmly united by the adhesive in which the fibers 12 and 13 areimbedded. The multiply reenforced paper so far described is strong,tough and durable, and is waterproof toa pronounced degree due to thefact that the inner face of each sheet of paper is coated with awaterproof adhesive which prevents the moisture that may come in contactwith the outer face of either sheet of paper from reaching thereenforcing fibers.

As above stated the present invention contemplates a reenforcedwaterproof paper such as above described and which is provided at spacedintervals with additional reeinforcing means to further strengthen thepaper at the points where the greatest wear and strain is likely tooccur.

The means of the present invention for further strengthening themultiply fabric constitutes reenforcing strips that may. be

either longitudinally or transversely or both longitudinally andtransversely of the multiply paper and these strips are shown in thedrawing as extending both longitudinally and transversely of the paperas indicated by 14 and 15. These strips may be formed of variousmaterials, such for example as spun or unspun fibers, woven fab-- r10,woven wire, or other reenforcing elements, and the strips 14 and 15 areshown in Figs. 1, 2, and 3, of the drawing as formed of unspun fibers oflong staple such for example as sisal, the fibers being disposed closetogether to provide the desired strength. In the modified constructionof Fig. 4 the reenforcing strip 16 is shown as formed of two sheets ofpaper having reenforcing fibers adhesively secured therebetween andextending longitudinally of the strips of paper. In the modification ofFig. 5 the reenforcing strip 17 is shown as formed of a woven matenal.

per 10 and 11, this is desirable in many cases due to the fact that thestrips when thus placed are protected from moisture and exposure andfrom abrasive action b the outor sheets of paper. The reenforcm stripsnecessarily increase the thickness of t e multiply paper somewhat at thelaces where these strips are provided and e stri are arranged so thatthey form a raise portion in only one outer sheet of paper as shown inFig. 3, or both sheets of aper may be displaced outwardly slightly w erethe strips occur as shown in Fi 4.

The tendency of t e paper employed in forming the multiply reenforcedfabric to tear under severe strains may be further reduced by crimping,craping or otherwise dis torting the sheets of paper from the flatcondition as shown in Fig. 5 in which the outer sheets 18 and 19 arecrimped or craped before the reenforcing elements are secured to thesesheets of paper, and as a result of this construction the crimped orcraped condition of the paper will permit it to stretch under tensionwithout rupturing while the strain is resisted by the reenforcingelements.

It will be seen from the foregoing that the reenforcing bands or strips14, 15, 16, and 17 may be made as strong as desired and if these bandsare so positioned that they will receive the greatest strain and wear towhich the reenforced paper is subjected the construction of the presentinvention may be employed for many purposes where it has been deemednecessary heretofore to employ a heavy woven fabric.

For example the reenforced waterproof paper of the present invention maybe employed as a substitute for canvas in constructing sails, tents,tarpaulins, and the like, and if care is taken to secure the grommets orother anchoring means to the reenforced sheet of paper at the pointswhere the additional strengthening strips are provided the paper will becapable of withstanding very severe strains. Likewise if the reenforcedpaper of the present invention is employed in the construction of sacks,bags, or bale wrappers it will'be capable of withstanding severe strainsif care is taken to place the reenforcing strips where they will receivethe greatest strain and wear to which the paper may be subjected. Thereenforced paper of the present invention in addition to the uses 1 justmentioned may also be employed as a blanket or covering for curingconcrete and as a covering for various other purposes since its strengthwill permit its use repeatedly without tearing.

Ill

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cured together where the increased strength and thickness is desired.

What is claimed is 1. As an article of manufacture, a multiplyreenforced fabric, comprising two sheets of paper secured together withwaterproof adhesive, reenforcing material secured between the sheets ofpaper by the adhesive, and means for further strengthening the multiplyfabric at predetermine points consisting of ribbon-like strips ofreenforcing material secured to the reenforced fabric structure atspaced intervals.

2. As an article of manufacture, a multiply, reenforced fabric,comprising two sheets of fibrous material secured together with anadhesive, a layer of reenforcing, unspun fibres secured between saidsheets by the adhesive, and means for further strengthening the multiplyfabric at spaced predetermined points comprising ribbon-like groups ofreenforcing fibres secured to the reenforced fabric structure at spacedintervals.

3. As an article of manufacture, a multiply, reenforced fabric,comprising two sheets of fibrous material secured together with awaterproof adhesive, a layer of straightened, unspun fibres extendinglongitudinally between said sheets and a second layer of straightened,unspun fibres extending transversely between said sheets and securedbetween the sheets by the adhesive, and means for further strengtheningthe multiply fabric at spaced predetermined points comprisingribbon-like roups of unspun fibres secured between said sheets at spacedintervals by the adhesive.

4. As an article of manufacture, a multiply, reenforced fabric, comrising two'sheets of fibrous material secure together with a waterproofadhesive, a layer of reenforcing, unspun fibres secured between saidsheets by the waterproof adhesive, and means for further strengtheningthe multiply fabric at speced predetermined points comprising narrowstrips of unspun, reenforcing material secured between said sheets atspaced intervals.

In testimony whereof, I have signed my name to this specification.

GEORGE E. GIBBS.

